The ratio between a two-digit number and the sum of the digits of that number is 4:1. If the digit in the unit place is 3 more than the digit in the ten's place, what is that number?

36

Let the ten's digit be $x$.

Then the unit's digit is $x + 3$.

So, the number is:

$10x + (x + 3) = 11x + 3$

The sum of the digits is:

$x + (x + 3) = 2x + 3$

Given:

$\frac{\text{Number}}{\text{Sum of digits}} = \frac{4}{1}$

$\frac{11x + 3}{2x + 3} = 4$

$11x + 3 = 8x + 12$

$3x = 9$

$x = 3$

Therefore:

• Ten's digit = 3
• Unit's digit = 6

Hence, the number is: 36